16.4.1.8 Replication of DROP ... IF EXISTS Statements

The DROP DATABASE
IF EXISTS,
DROP TABLE IF
EXISTS, and
DROP VIEW IF
EXISTS statements are always replicated, even if the
database, table, or view to be dropped does not exist on the
master. This is to ensure that the object to be dropped no
longer exists on either the master or the slave, once the slave
has caught up with the master.

Beginning with MySQL 5.1.33, DROP ... IF
EXISTS statements for stored programs (stored
procedures and functions, triggers, and events) are also
replicated, even if the stored program to be dropped does not
exist on the master. (Bug #13684)